Message-ID: <20160816073436.GA3889@pc>
Date:	Tue, 16 Aug 2016 08:34:36 +0100
From:	Salah Triki <salah.triki@...il.com>
To:	Luis de Bethencourt <luisbg@....samsung.com>
Cc:	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
	viro@...iv.linux.org.uk, salah.triki@....org
Subject: Re: [PATCH 2/3] befs: improve documentation in datastream.c

On Sat, Aug 13, 2016 at 06:11:20PM +0100, Luis de Bethencourt wrote:
> Convert function descriptions to kernel-doc style.
> 
> Signed-off-by: Luis de Bethencourt <luisbg@....samsung.com>
> ---
>  fs/befs/datastream.c | 193 ++++++++++++++++++++++++++-------------------------
>  1 file changed, 98 insertions(+), 95 deletions(-)
> 
> diff --git a/fs/befs/datastream.c b/fs/befs/datastream.c
> index b2eb5b5..5ce85cf 100644
> --- a/fs/befs/datastream.c
> +++ b/fs/befs/datastream.c
> @@ -75,7 +75,13 @@ befs_read_datastream(struct super_block *sb, const befs_data_stream *ds,
>  	return bh;
>  }
>  
> -/*
> +/**
> + * befs_fblock2brun - give back block run for fblock
> + * @sb: the superblock
> + * @data: datastream to read from
> + * @fblock: the blocknumber with the file position to find
> + * @run: The found run is passed back through this pointer
> + *
>   * Takes a file position and gives back a brun who's starting block
>   * is block number fblock of the file.
>   * 
> @@ -212,36 +218,35 @@ befs_count_blocks(struct super_block *sb, const befs_data_stream *ds)
>  	return blocks;
>  }
>  
> -/*
> -	Finds the block run that starts at file block number blockno
> -	in the file represented by the datastream data, if that 
> -	blockno is in the direct region of the datastream.
> -	
> -	sb: the superblock
> -	data: the datastream
> -	blockno: the blocknumber to find
> -	run: The found run is passed back through this pointer
> -	
> -	Return value is BEFS_OK if the blockrun is found, BEFS_ERR
> -	otherwise.
> -	
> -	Algorithm:
> -	Linear search. Checks each element of array[] to see if it
> -	contains the blockno-th filesystem block. This is necessary
> -	because the block runs map variable amounts of data. Simply
> -	keeps a count of the number of blocks searched so far (sum),
> -	incrementing this by the length of each block run as we come
> -	across it. Adds sum to *count before returning (this is so
> -	you can search multiple arrays that are logicaly one array,
> -	as in the indirect region code).
> -	
> -	When/if blockno is found, if blockno is inside of a block 
> -	run as stored on disk, we offset the start and length members
> -	of the block run, so that blockno is the start and len is
> -	still valid (the run ends in the same place).
> -	
> -	2001-11-15 Will Dyson
> -*/
> +/**
> + * befs_find_brun_direct - find a direct block run in the datastream
> + * @sb: the superblock
> + * @data: the datastream
> + * @blockno: the blocknumber to find
> + * @run: The found run is passed back through this pointer
> + *
> + * Finds the block run that starts at file block number blockno
> + * in the file represented by the datastream data, if that
> + * blockno is in the direct region of the datastream.
> + *
> + * Return value is BEFS_OK if the blockrun is found, BEFS_ERR
> + * otherwise.
> + *
> + * Algorithm:
> + * Linear search. Checks each element of array[] to see if it
> + * contains the blockno-th filesystem block. This is necessary
> + * because the block runs map variable amounts of data. Simply
> + * keeps a count of the number of blocks searched so far (sum),
> + * incrementing this by the length of each block run as we come
> + * across it. Adds sum to *count before returning (this is so
> + * you can search multiple arrays that are logicaly one array,
> + * as in the indirect region code).
> + *
> + * When/if blockno is found, if blockno is inside of a block
> + * run as stored on disk, we offset the start and length members
> + * of the block run, so that blockno is the start and len is
> + * still valid (the run ends in the same place).
> + */
>  static int
>  befs_find_brun_direct(struct super_block *sb, const befs_data_stream *data,
>  		      befs_blocknr_t blockno, befs_block_run * run)
> @@ -273,29 +278,28 @@ befs_find_brun_direct(struct super_block *sb, const befs_data_stream *data,
>  	return BEFS_ERR;
>  }
>  
> -/*
> -	Finds the block run that starts at file block number blockno
> -	in the file represented by the datastream data, if that 
> -	blockno is in the indirect region of the datastream.
> -	
> -	sb: the superblock
> -	data: the datastream
> -	blockno: the blocknumber to find
> -	run: The found run is passed back through this pointer
> -	
> -	Return value is BEFS_OK if the blockrun is found, BEFS_ERR
> -	otherwise.
> -	
> -	Algorithm:
> -	For each block in the indirect run of the datastream, read
> -	it in and search through it for	search_blk.
> -	
> -	XXX:
> -	Really should check to make sure blockno is inside indirect
> -	region.
> -	
> -	2001-11-15 Will Dyson
> -*/
> +/**
> + * befs_find_brun_indirect - find a block run in the datastream
> + * @sb: the superblock
> + * @data: the datastream
> + * @blockno: the blocknumber to find
> + * @run: The found run is passed back through this pointer
> + *
> + * Finds the block run that starts at file block number blockno
> + * in the file represented by the datastream data, if that
> + * blockno is in the indirect region of the datastream.
> + *
> + * Return value is BEFS_OK if the blockrun is found, BEFS_ERR
> + * otherwise.
> + *
> + * Algorithm:
> + * For each block in the indirect run of the datastream, read
> + * it in and search through it for search_blk.
> + *
> + * XXX:
> + * Really should check to make sure blockno is inside indirect
> + * region.
> + */
>  static int
>  befs_find_brun_indirect(struct super_block *sb,
>  			const befs_data_stream *data,
> @@ -365,47 +369,46 @@ befs_find_brun_indirect(struct super_block *sb,
>  	return BEFS_ERR;
>  }
>  
> -/*
> -	Finds the block run that starts at file block number blockno
> -	in the file represented by the datastream data, if that 
> -	blockno is in the double-indirect region of the datastream.
> -	
> -	sb: the superblock
> -	data: the datastream
> -	blockno: the blocknumber to find
> -	run: The found run is passed back through this pointer
> -	
> -	Return value is BEFS_OK if the blockrun is found, BEFS_ERR
> -	otherwise.
> -	
> -	Algorithm:
> -	The block runs in the double-indirect region are different.
> -	They are always allocated 4 fs blocks at a time, so each
> -	block run maps a constant amount of file data. This means
> -	that we can directly calculate how many block runs into the
> -	double-indirect region we need to go to get to the one that
> -	maps a particular filesystem block.
> -	
> -	We do this in two stages. First we calculate which of the
> -	inode addresses in the double-indirect block will point us
> -	to the indirect block that contains the mapping for the data,
> -	then we calculate which of the inode addresses in that 
> -	indirect block maps the data block we are after.
> -	
> -	Oh, and once we've done that, we actually read in the blocks 
> -	that contain the inode addresses we calculated above. Even 
> -	though the double-indirect run may be several blocks long, 
> -	we can calculate which of those blocks will contain the index
> -	we are after and only read that one. We then follow it to 
> -	the indirect block and perform a similar process to find
> -	the actual block run that maps the data block we are interested
> -	in.
> -	
> -	Then we offset the run as in befs_find_brun_array() and we are 
> -	done.
> -	
> -	2001-11-15 Will Dyson
> -*/
> +/**
> + * befs_find_brun_dblindirect - find a block run in the datastream
> + * @sb: the superblock
> + * @data: the datastream
> + * @blockno: the blocknumber to find
> + * @run: The found run is passed back through this pointer
> + *
> + * Finds the block run that starts at file block number blockno
> + * in the file represented by the datastream data, if that
> + * blockno is in the double-indirect region of the datastream.
> + *
> + * Return value is BEFS_OK if the blockrun is found, BEFS_ERR
> + * otherwise.
> + *
> + * Algorithm:
> + * The block runs in the double-indirect region are different.
> + * They are always allocated 4 fs blocks at a time, so each
> + * block run maps a constant amount of file data. This means
> + * that we can directly calculate how many block runs into the
> + * double-indirect region we need to go to get to the one that
> + * maps a particular filesystem block.
> + *
> + * We do this in two stages. First we calculate which of the
> + * inode addresses in the double-indirect block will point us
> + * to the indirect block that contains the mapping for the data,
> + * then we calculate which of the inode addresses in that
> + * indirect block maps the data block we are after.
> + *
> + * Oh, and once we've done that, we actually read in the blocks
> + * that contain the inode addresses we calculated above. Even
> + * though the double-indirect run may be several blocks long,
> + * we can calculate which of those blocks will contain the index
> + * we are after and only read that one. We then follow it to
> + * the indirect block and perform a similar process to find
> + * the actual block run that maps the data block we are interested
> + * in.
> + *
> + * Then we offset the run as in befs_find_brun_array() and we are
> + * done.
> + */
>  static int
>  befs_find_brun_dblindirect(struct super_block *sb,
>  			   const befs_data_stream *data,
> -- 
> 2.5.1
> 

Signed-off-by: Salah Triki <salah.triki@...il.com>

Thanks,
Salah

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